ML20217D174

Forwards Remaining Difference Between Staff Final SE & Revised BWRVIP-07 Document Concerning Table 1,core Shroud Reinspection Intervals for Category C Plants.Determined That Addition of Listed Words to Note 4,necessary

ML20217D174
Person / Time
Issue date:	10/06/1999
From:	Bateman W NRC (Affiliation Not Assigned)
To:	Terry C NIAGARA MOHAWK POWER CORP.
References
NUDOCS 9910150040
Download: ML20217D174 (5)

Text

'

i

.~

~

p k

UNITED 8 TATE 8

,p' g -

NUCLEAR REGULATORY COMMISSION -

. WASHINGTON, D.C. 30005 4 001 6

-October 6, 1999 Carl Terry, BWRVIP Chairman

' Niagara Mohawk Power Company. -

Post Office Box 63 Lycoming, NY.13093

SUBJECT:

STAFF REEVALUATION OF TABLE 1 IN THE BWRVIP-07 REPORT (TAC NO. M94959)-

Dear Mr. Terry:

By letter dated August 13,1999, we provided to you the' staff's re-evaluation of Table 1, Core Shroud Reinspection Intervals for Category C Plants, from the Electric Power Research

Institute's (EPRI) Report TR-105747, "BWR Vessel and Intemals Project, Guidelines for

. Reinspection of BWR Core Shrouds (BWRVIP-07)."

The BWRVIP-07 report was provided to the NRC for staff evaluation in a letter dated February 29,1996, and was supplemented by letters dated Ju!y 17, May 21, and October 21,1996, and January 8,1997. On September 15,1997, the staff issued its initial safety evaluation (SE) of the BWRVIP-07 report. The staff found the guidance to be generally accyab'c but identified several open issues. The staff completed its review of the information provided by the BWRVIP

. In its supplemental letters, and issued a supplement to its initial SE dated Apal 28, %98, to close the.open issues.

The remaining difference between the staff's final SE and the revised BWRViP-07 document

. concemed the reinspection intervals (in years) for Category C plants, contained in Table 1,

Core Shroud Reinspection Intervals for Category C Plants, of the BWRVIP-07 report. After discussions with the BWRVIP during the public meeting on July 21,1999, (see meeting '

summary dated August 10,1999), the staff agreed to the industry usage of the revised Table 1.

L

. Further, trie staff agreed to re-evaluate this issue when the BWRVIP submits a consolidated j

and revised core shroud inspection and flaw evaluation guideline that incorporates the guidance

~

presently contained in the BWRVIP-01, -07,~and -63 reports, and which will address the high fluence levels expected at etd of license.

' However, there has been confusien by the industry in the a'ppropriate interpretation of the l

' revised Table 1.- In order to provide adequate clarification regaruing the interpretation of 1

Table 1, the staff has determined that the addition of the following boMed and italicized words to Note 4 are necessary:'

p 4.

Applies to welds with cracking 210 percent where neutron fluence is greater than 3 x 10" nicm', andless than 5 x 19" nicm'(E > 1MeV). For fluences exceeding

?

5 x 10" nicm', a plant-specific analysis is required to be submitted to the NRC.

h- / [

h

-l 9910150040 991006 l.

PDR TOPRP EXIEPRI

'C PDR

' M.EO! $$ns'RDM

<FA31 m

m k

r a.

[. :.

t-t j

Carl T,erry,

l Also, clarification was added to the, " Percent Cracking' column of the Table and to Note 2.

Crack lengths should be munded gg to the next whole number.

Please contact C. E. (Gene) Carpenter, Jr., of my staff at (301) 415-2169 if you have any further questions regarding thle subject.

Sincerely, theM William H. Bateman, Chief Materials and Chemical Engineering Branch Division of Engineering Office of Nuclear Reactor Regulation

Enclosure:

As stated

[

cc: See next page.

k

/

~

b.

cc:

Bill Eaton, Executive Chair Carl Laie.,, Technical Chairman inspection Committee '

BWRVIP inspection Task Entergy Operations, Inc.

P.O. Box 157 PO Box 756, Waterloo Rd Vernon, VT 05354 Port Gibson, MS 39150-0756 H. Lewis Sumner, Executive Chairman John Wilson, Technical Chairman BWRVIP Mitigation Task BWRVIP Mitigation Task Southern Nuclear Operating Co.

Clinton Power Station, WC T-31C WS BIN B051, PO E0x 1295 P.O. Box 678 40 inverness Center Parkway Clinton,IL 61727 Birmingham, AL 35201 Harry P. Salmon, Executive Chairman Vaughn Wagoner, Technical Chairman BWRVIP Integration Task BWRVIP Integration Task New York Power Authority Carolina Power & Light Company 123 Main St., WS 11 D One Hannover Square 901 White Plair.s, NY 10601-3104 P.O. Box 1551 Raleigh, NC 27612 George T. Jones, Executive Chair Bruce McLeod, Technical Chairman l

' BWRVIP Repair Task BWRVIF' Repair Task Pennsylvania Power & Light, Inc.

Southern Nuclear Operating Co.

WS GEN A 61 Post Office Box 1295 2 N 9* Street 40 Inverness Center Parkway Allentown, PA 18101-1139 Birmingham, AL 35201 4

Robert Carter, EPRI BWRVIP Tom Mulford, EPRI BWRVIP Assessment Manager Integration Manager Greg Selby, EPRI BWRVIP Raj Pathania, EPRI BWRVIP inspection Manager Miti0ation Manager EPRI NDE Center Ken Wolfe, EPRI BWRVIP P. O. Box 217097 Repair Manager 1300 W. T. Harris Blvd.

Electric Power Research Institute Charlotte, NC 28221 P. O. Box 10412 3412 Hillview Ave.

Joe Hagan, BWRVIP Vice Chairman Palo Alto, CA 94303 PEPCO Energy Co.

MC 62C-3 James P. Pelletier, BWRV!P Liaison 965 Chesterbrook Blvd to EPRI Nuclear Power Council Wayne, PA 19807-5691 Nebraska Public Power District 1200 Prospect Avenue Steve Lewis, Technical Chairman PO Box 98 BWRVIP Assessment Task Brownville, NE 68321-0098 Entergy P. O. Box 756 Waterloo Road Port Gibson, MS 39150

j f

Core Shroud Reinspection Intervals for Category C Plants (in years) 4 Percent Stress") = 1 ksl Stress") = 3 kai 0

Stress )= 6 kai Cracking"' 8)

Limit Load.

LEFM(*)

Limit Load LEFM(*)

Limit Load LEFM(')

x < 10 10.0 10.0 10.0 10.0 10.0 10.0 20 < x s 10 10.0 10.0 10.0 10.0 10.0 6.0 25 < x s 20 6.0.

6.0 6.0 6.0 6.0 6.0 30 < x s 25 6.0 6.0 6.0 6.0 6.0 x230 Notes:

1. Length of weld inspectsd must be at least 50 percent of the weld circumference

2. Cracking is defined as the total length of as-found cracks as a percentage of the total length inspected for each weld. If the sizing uncertainty for the inspection method used exceeds

" (0.4" + 0.5') in length at a flaw end, the amount above this should be included in the amount of cracking. Crack lengths should be rounded gg to the next whole number.

3. Stress values are for faulted loading conditions. Interpolation between stress values is acceptable.

4.. Applies to welds with cracking 210 percent where neutron fluence is greater than 3 x 10 '

8 n/cm', and less than 5 x 10 ' n/cm' (E > 1MeV). For fluences exceeding 5 x 10' n/cm', a plant-specific analysis is required to be submitted to the NRC.

5. Linear extrapolation of the reinspection intervals is permitted up to a value of 10 ksi. Values should be capped (or rounded down) at values consistent with the approach in the above

table, i

6. Plant specific andysis is required.

I i

I i

ENCLOSURE

o Carl Terry 1 l

L Also, clarification was added to the " Percent Cracking" column of the Table and to Note 2.

Crack lengths should be rounded.yp to the next whole number.

j

\\

Please contact C. E. (Gene) Carpenter, Jr., of my staff at (301) 415-2169 if you have any further questions regarding this subject.

Sincerely, William H. Bateman, Chief -

Materials and Chemical Engineering Branch.

Division of Engineering _

Office of Nuclear Reactor Regulation

Enclosure:

As stated cc: See next page DISTRIBUTION:

EMCB R/F JRStrosnider GHolahan WDLanning, R1 PUBLIC RHWessman MEMayfield BSMallet, R2

File Centei,a,R,/

KRWichman TYChang JGrobe, R3

'ACRS-AHowell, R4 j

p Document Name: G:\\BWRVIP\\BWRVIP07 Table 1 Rev2.WPD i

WDICATE M DOX:"C"= COPY W/O ATTACHMENT / ENCLOSURE, *E"= COPY W/ATTENCL,"N' COPY EMCB: LPM lE EMCB:SLS

'lE EMCB:BC j

CECarpenter, j RAHermaAg WHBatemagj%

1 09/10/1999 [DL 09//P/1999 Mb/1999 OFFICIAL RECORD COPY 1

i u

J